(a) Field of the Invention
The present invention relates means for removably coupling a printing disc on a printing machine drive shaft and more particularly provides a bracket secured to the drive shaft and having a planar face to the disc engaged thereon during the course of a radial displacement, one of the disc and bracket having clamp means securable and, additionally to the other, and resilient cooperable coupling means formed on the disc and bracket whereby angular as well as radial movement of the disc on the drive shaft is prevented.
(b) Description of the Prior Art
Removable securement of printing discs of the type, also known as daisy printing wheels, onto the driving shaft of a printing machine gives rise to delicate problems by reason of the diverse conditions which have to be fulfilled.
For example, the mounting and the removing of the printing disc must be easy and rapid in order to enable the user of the machine rapidly to change the disc when he wants to change the printing type. The securing of the disc on the drive shaft must be reliable and must resist dislodgement under the accelerations and decelerations of very high rotational speed to which the disc is subjected in use. Additionally, the radial and angular position of the disc with respect to the drive shaft must be perfectly precise.
Prior attempts to provide constructive solutions to these problems have been suggested, but none of them is entirely satisfactory to meet all the criteria referred to hereinabove. It would be of considerable advantage to provide a single structure meeting the above criteria.